The sound quality of cassette tapes may be crappy, but for anyone who misspent their youth in the '80s and '90s, their memory quality is superior. Every person who has ever made a mix tape has probably written about mix tapes. There are mix-tape websites, songs about mix tapes, and now, a mix-tape book. Indeed, mix tapes are so ubiquitous that it seems silly even to define them. Aptly titled, Mix Tape: The Art of Cassette Culture (Universe; $22) attempts to do this for us.

Edited by Thurston Moore, the hyperactive guitarist of Sonic Youth, Mix Tape is more of a coffee-table patchwork of words and images than an assay into the subject. In its pastiche of scanned cassette-tape inserts and hand-written song lists, folks from the worlds of music, art and fashion share mix tapes or memories of long-lost mix tapes that are particularly meaningful to them. There are voyeuristic kicks in reading about a then 15-year-old Jim O'Rourke making mix tapes to get girls to like him, or in looking over the songs on a tape that the Flaming Lips' Steven Drozd made for Mike Watt and noticing that he included Glen Campbell's "Wichita Lineman."

It's cool to compare mix-tape artwork in the book, how some people painstakingly piece together collages of magazine clippings with Scotch tape while others skip the covers altogether, and it's especially gratifying to see how often songs from the Modern Lovers' first album and the Association's "Windy" appear on mixes over the ages.

Mix Tape sure has a lot of love for mix tapes, but it's more gloss than substance. Mainly, it fails to ask why we made mix tapes. The initial urge may have been to collect songs you liked in one handy place, but ultimately no one made mix tapes for convenience. The mere process of making one--fast forwarding, pausing, rewinding ad infinitum with a collapse tower of cassette tape cases spread all over the floor--requires too much commitment to not have a deeper motive.

Making a mix tape confers ownership. Unlike people, songs are always available and can be arranged just so. Putting a song on a mix tape is like placing it in a shrine; it confirms its greatness, and that power of placement is extremely gratifying. I can't even play a tambourine right, but I can record songs by Leadbelly, Cher and Beck back-to-back and feel that I've not only participated in music, but made it. That's because on a good mix tape, order is everything. If you get the right flow going, it's possible to move from Donovan to the My Fair Lady soundtrack to Wilco without losing continuity.
Outside of communion with music, the most compelling motive for mixing a tape is to create that perfect Unrequited-Love Mix Tape, aka the Mix Tape as Self-Portrait. Even when we make mix tapes for other people--especially when we make mix tapes for other people--we make them for ourselves.

The rapid decline of the cassette leaves the fate of mix tapes in question. Sure, there are CDRs and iPod playlists, but they really are not the same thing. It's my feeling that a CD mix is too easily dashed off with a few clicks of a mouse, and that the impossibility of assessing each song as it plays impedes continuity of the music's tone. Besides, cassette tapes have two sides, allowing for a first act, an intermission and a second act.

Even so, I've switched over to making mix CDs now myself, because how can you be sure that someone has a tape deck? I still have all of my old mix tapes; disposing of a mix tape is like throwing away a handwritten letter. My friends and I don't sit around sifting through cassettes and fussing over cover art for each other anymore, perhaps because we are now adults and don't have much drive to mirror our flawed, innocent selves in music. But I can conjure exact images of our ex-selves with the click of a play button and in the wow and flutter of thinning magnetic tape, as beautiful in its hiss as medieval manuscripts are in their decay.